Grinding machine



1940- J. v. BERGFELDT GRINDING MACHINE Filed July 27, 1958 4 Sheets-Sheet 1 JUL/Us Vfizzearapr Nov. 19, 1940.

J. v. BERGFELDT 2,222,580

GRINDING MACHINE Filed July 27, 1938 4 Sheets-Sheet 4 Patented Nov. 19,1940 UNITED. STATES PATENT OFFICE GRINDING MACHINE Julius V. Bergfeldt,New Britain, Conn.

Application July 27, 1938, Serial No. 221,499

4 Claims. (Cl. 51134) The present inventionrelates to .grindingniachines and more particularly to a grinder having a plurality of workholding chucks rotatably carried past one or more grinding wheels.

The object of the present invention is an improved machine of theabove-indicated type wherein there is provided a rotating work tablehaving a plurality of work holding chucks thereon and one or moregrinding wheels located above the work table and adapted to surfacegrind the work carried in the chucks.

A still further object is a grinding machine having improved means formaintaining the grinding surfaces of the wheels sized and dressedwithout interruption in the operation of the machine.

A still further object is-a machine having improved means for feedingthe grinding wheels toward the work and including means for controllingsuch feed in timed relationship to the rotation of the feed table.

A still further object is a machine wherein the speed of the grindingwheels may be varied and including improved variable driving means.

Other objects will be in part obvious and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements, and arrangement of parts which will .beexemplifled in the construction hereafter set forth and the scope of theapplication of which will be indicated in the appended claims.

In the accompanying drawings:

Figure 1 is a front view of a machine embodying the invention herein;

Fig. 2 is a plan view of Fig. 1;

Fig. 3 is a detail view of the manual and automatic means for feedingthe grinding wheel shafts;

Fig. 4 is a sectional view on the line 4--4 of Fig. 3;

Fig. 5 is a view partially in section of the variable driving means;

Fig. 6 is a sectional view of the variable drive pulley assembly;

Fig. '7 is a fragmentary sectional view of a grinding wheel shaft andthe feeding spindle therefor; and

Fig. 8 is a detail view of the variable drive supporting bracket.

Referring to the drawings, the machine includes a cylindrical supportingbase III in which there is centrally located a shaft l2 on which ismounted a rotatable work holding table M, the diameter of which issomewhat less than the di ameter of the supporting base It. Intermediateof the periphery I! of the work supporting table I4 and the periphery llof the base In, the base is provided with a horizontally arranged outertop plate l6 and an inner top plate l8; the inner top plate being spacedbelow the outer plate l6 by a vertically arranged shoulder 20. The workholding table I4 is adapted to be rotated about the shaft I! by anysuitable variable drive mechanism which may be located in the base 10,which drive mechanism has been omitted for purpose of simplicity. V

The work table carries a plurality of work holding chucks 22 which havebeen shown more or less diagrammatically and are provided with suitablejaws adapted to be closed for a portion of rotation of the table andopened during the remainder of the rotation to allow the work pieces tobe readily removed therefrom and new work pieces placed therein. Thejaws of each chuck are automatically opened and closed by a plunger 24provided on its outer end with a roller or follower 26 which is springpressed into engagement with the vertical surface of the shoulder 20during the angle of rotation in which the jaws are open and adapted toreceive the work holding pieces. The follower is adapted to ride over acam 28 arranged on the shoulder 20 for urging the plunger inwardly toclose the jaws during the angle of rotation in which the work piecesmust be securely held.

Th work pieces are thus rotated beneath s'uitable grinding wheels 30which are vertically carried on a support 32 which extends upwardly fromthe top plate It and carries a substantially triangular shaped housing34, which housing overhangs the inner top plate l8 of the base It) andthe work holding chucks of the rotatable table i l, with the apex of thehousing being closest to the center shaft I2, as viewed in Fig. 2. Thesides 36 and 38 of the housing are arranged at right angles to oneanother, and each side makes an angle of with a diameter extendingthrough the center of the shaft l2 and the apex of the housing.

The housing provides a duplex support for the grinding wheels 30 andtheir associated driving mechanism, and inasmuch as the construction ofeach is identical, only one will be described, with like numbers appliedto the other. As best seen from Figs. 4 and 5, there is mounted on eachside wall 36, by suitable bolts 40, a vertically arranged base plate 42.The upper portion of the base plate 42 has secured thereon an upperspindle housing 44 and shaft housing 46. The

lower portion of the base plate 42 has bolted thereon suitable ways 48in which there are slidably mounted a lower spindle housing 50 and shafthousing 62. The uI-per and lower shaft housings 46 and 52 are providedwith aligned bores for receiving a grinding wheel shaft which isprovided on its lower end with a grinding wheel supporting plate 56 onwhich the grinding wheel 30 may be secured in any suitable way.

The portion of the shaft 54 which is positioned in the lower shafthousing 52 isprovided with upper and lower threaded portions 58 (theupper end being shown in Fig. 7) the threaded portions being adapted toreceive a securing nut 60 adapted to position therebetween suitableupper and lower ball bearing races 62 and a spacing sleeve 64.Positioned between the nut 60 and the top plate of the housing 52 theremay be provided any suitable spacer 66 to cause simultaneous verticalmovement of the housing 52 and the shaft 54 for raising and lowering thedrive shaft and grinding wheel, as hereinafter explained.

The drive shaft 54 extends above the housing 52 and into a sleeve 68rotatably mounted in the upper shaft housing 46; the shaft beingsuitably keyed in the sleeve to permit vertical movement relativethereto. The upper end of the sleeve 68 extends above the housing 46 andhas secured thereon a drive pulley 10 having atop and bottom groovetherein. The pulley 10 connects through suitable driving belts I2 and I4to a pair of pulleys "Sand 18 arranged on the upper end of anintermediate driving member the lower end thereof carrying a pair ofpulleys 82 and 84, which in turn connect through suitable belts 86 and88 to a pulley mounted for rotation on a shaft 92 of a drive motor 94.

As may best be seen in Fig. 2, the motor 94 is mounted on a wall 06extending at right angles to the wall 36 of the housing 34, and theintermediate driving member 80 is adjustably mounted on a bracket 98,which bracket is secured to a wall I00 positioned within the housing 34.The intermediate driving member 80 may be adjusted to vary the speed ofthe grinding wheel 30, and to accomplish this the member 80 comprises acenter shaft I02 rotatably supported in a bracket I04, which bracket isprovided with a shoe I06 mounted for slidable movement in the ways I08of the supporting bracket 98. The ways I08 are arranged at an angle of15 to the horizontal, whereupon movement of the bracket I04 will movethe shaft I02 transversely of the wall I00. In order to transmit theangular movement of the member I02, the various driving pulleys anddriving belts heretofore mentioned are provided with cooperating groovesand drive surfaces, all of which taper at an angle of 15 to thehorizontal.

The upper and lower sets of pulleys on the shaft I02 each comprisesindependent cooperating members adapted to be moved toward and away fromone another and are so arranged that upon transverse movement of theshaft I02 the upper and lower pulleys will open out or close in inopposed relationship to one another (see Fig. 6). To accomplish this,the upper member IIO of the pulley 16 is spaced from the upper member II2 of the pulley I8 by a sleeve I I4; the pulley members I I0 and I I2being mounted on a reduced portion II6 of the shaft I02, with the pulleymember II2 abutting against the upwardly facing shoulder I I8intermediate of the enlarged and reduced portions of the shaft I02. Thelower member I20 of the pulley I6 is mounted on the outer surface of thesleeve 4 and connects through suitable bolts I22 which extend throughthe member II2 to the lower member I24 of the pulley I8; the member I24being mounted on the outer surface of a sleeve I26 which is rotatablymounted in the bracket I04 and in which the shaft I02 may be movedvertically.

The lower set of pulleys 82 and 34 are similarly constructed andcorresponding parts have been correspondingly numbered, with the suffixa" added thereto. With this arrangement, the pulley members I24 and I24aare spaced apart at a fixed distance by the sleeve I26 and theinterposed ball bearing races I28, and upon adjustment of the bracketI04 the members I24 and I240, will be moved transversely andsimultaneously raised or lowered, depending upon the direction ofmovement of the bracket. Thus if the bracket I04 is moved to the left,as viewed in Fig. 6, the members I24 and I24a will be raised and willsimultaneously cause the members I20 and I20a, which are connectedthereto, to be raised. As the tapered surfaces of these members rideover the tapered surfaces of the connecting belts, the shaft I02 will bedrawn downwardly, thus causing the members of the upper set of pulleysI6 and 18 to close in and the members of the lower sets of pulleys toopen out, thus changing the position of the belts on the drivingsurfaces and varying the speed from the motor 54 to the pulley I0.

The bracket I04 may be adjusted to adjust the variable stepless pulleysby a suitable threaded stem I30 which extends into a threaded openingtherein and projects outwardly therefrom and through a sleeve I32 in therear wall I34 of the housing 34; the stem being prevented fromlongitudinal movement in the'sleeve by a suitable collar I36 and themanually operable handle I38. Thus it will be seen that the speedvariation of the grinding wheel has an infinite range which not onlypermits the variation of the speed of any one grinding wheel, but allowsthe use of various sizes of grinding wheels on the same drive shaft.

There is also provided means for lowering and raising the grinding wheeltowards and from the work holding pieces, and to accomplish this thereis mounted in the upper spindle housing 44 the reduced upper end of aspindle I40 (see Fig. '7) which extends through a suitable bore I42 andis secured in place by a nut I44 and held against rotation by a key I46.The spindle extends down and through an aligned bore in the lowerspindle housing 50, which housing has rotatably mounted therein a sleeveI48 correspondingly threaded to and adapted to be rotated on the spindleI40.

The lower end of the sleeve I48 terminates in a bevel gear I50 whichcooperates with a bevel gear I52 secured on the inner end of a controlshaft I54 (see 'Fig. 4), which shaft extends through and out of theshaft housing 52 and has secured on its outer end a suitable manuallyoperable control wheel I56. Upon rotation of the wheel I56, the shaftI54 will rotate gear I52 to cause rotation of the bevel gear I50 and thesleeve I48, whereupon the sleeve I48 will move vertically on the spindleI40 to move the shaft housing 52 and grinding wheel shaft 54 up or down,depending upon the rotation of the control wheel, and thus adjust thegrinding wheel relative to the work pieces.

As it is desirable to automatically lower the grinding wheel 30 towardsthe work pieces, there is positioned intermediate of the shaft housing52 7 and the manual control wheel I56 a ratchet wheel I58 which issecured in any suitable way to a sleeve I60 splined onto the shaft I54for simultaneous rotation therewith. The wheel I58 is en- .closed in ahousing I62 having mounted therein a ratchet dog I64 which is normallyspring pressed into engagement with the ratchet wheel I58 and may becammed out of engagement therewith by a manually operable lever I66 whenit is desired to manually operate the shaft I54 and raise or lower thehousing.

The housing I62 is mounted for rotation about the shaft I54 and sleeveI60 and is provided with a rearwardly extending link I68 which connectsto the depending lever I10 of a solenoid I12. The weight of the solenoidand the connecting linkage I68 and I10 is such as to normally rotate thehousing I62 in a clockwise direction, as viewed in Fig. 3, to positionthe ratchet dog I64 under one of the teeth of the ratchet wheel I58. The

housing I62 is also provided with a laterally ex-- movement of thehousing I 62 and thus vary the number of teeth over which the ratchetdog I64 rides and control the amount of feed of the grinding wheel.

The solenoid I12 is normally de-energized (see Fig. 3) and becomesenergized upon the closing of a suitable switch mounted on the outerplate I6 of the base I0 (see Fig. 2) which switch I86 is periodicallyactuated by a cam member I90 carried on a supporting plate I92 securedto the rotatable work holding table I4. Upon closure of the switch I88,the solenoid I12 will become energized (through suitable connections notshown) to rotate the housing I62 in a counterclockwise direction,whereupon the dog I 64 will rotate the ratchet wheel I58 to rotate shaftI54 and lower the grinding wheel 30 a predetermined amount, dependingupon the setting of stops I18 and I80. Upon the automatic opening ofswitch I88, the solenoid will become de-energized, and the weight of theassociated linkage as heretofore described will rotate the housingclockwise to position the dog I64 for the next lowering operation.

Another improvement in the presentgrinding machine is the provision ofmeans for sizing and dressing the grinding wheels 30 at predeterminedtimes during the revolution of the table I4. In the embodimentillustrated, the wheels are adapted to be sized and dressed once duringeach revolution, and to accomplish this there is provided a pair ofspaced apart diamonds I64 and I96 vertically arranged on the supportingplate I92. As

beneath the roughing wheel and will engage same intermediate of thecenter and the outer periphery'thereoi', and thus in sizing and dressingof the wheel it will do so without hollowing out or giving the wheel aconcave surface. 5 The diamond I96'is so spaced from the diamond I84that it will pass inwardly of the roughing wheel. However, upon furtherrotation of the table, the diamond I96 will engage the finishing wheelintermediate of the center and the inside periphery thereof; whereas thediamond I94 will clear the finishing wheel. It will be noted that thesupporting plate I92 is positioned just ahead of the first open chuckinto which anew piece of work has been placed. Upon rotation of thetable, the cam I90 will cause the grinding wheel to be loweredimmediately after the last piece of work has been ground by the wheeland immediately before the sizing and dressing diamond I84 contacts thewheel. Thus when the wheel engages the next piece of work, it will beproperly sized and dressed to rough grind the work a predeterminedamount. Upon further rotation, the cam I90 will engage the second switchI88 to lower the finish grinding wheel into position to be operated uponby the finishing diamond I96.

It is apparent that if the type of work is such that more than onesizing and dressing of the wheels is required, a plurality of supportingplates and diamonds could be positioned around the periphery of therotating table I4. As it is sometimes desirable to arrange the lowersurface of the grinding wheels oil? the horizontal, the base plate 42(see Fig. 5) is provided with an adjustment stud I08, which stud may bescrewed in against the wall surface 36 to tilt the supporting plate 42.Inasmuch as the amount of tilt in grinding work is only a matter ofthousandths, the required amount may be accomplished without disturbingthe securing hold of 40 the bolts 40.

From the foregoing, the operation of the machine appears abvious; itbeing apparent that once, the machine is placed in operation andproperly adjusted for the particular type of 45 work to be ground theentire operation there after will be automatic.

As many changes could be made in the above construction and manyapparently widely difierent embodiments of this invention could be made'without departing from the scope thereof, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense. 55

It is also to be understood that the language used in the followingclaims is intended to cover all of the generic and specific features ofthe invention herein described and all statements of the scope of theinvention which, as a matter of 60 language, might be said to falltherebetween.

I claim as my invention:

1. In a machine of the character described, a rotatable work holdingtable, a pair of grinding wheels supported above said table, each ofsaid 65 grinding wheels having a fiat radial grinding surface facing thework holding table, a pair of sizing and dressing means carried by saidtable,

rotatable work holding table, a pair of grinding wheels supported abovesaid table, each of said grinding wheels having a flat radial grindingsurface facing the work holding table, one of said grinding wheels beingat a greater radius from the center than the other, a pair of sizing anddressing means carried by said table, one of said sizing and dressingmeans being at a greater radius from the center than the other andadapted to size and dress the radial surface of the grinding wheel atthe greater distance from the center and clear the wheel at lesserdistance, said other sizing and dressing means being adapted to size anddress the radial surface of the other grinding wheel and clear the wheelat greater distance.

3. In a machine of the character described, a rotatable work holdingtable, a grinding wheel positioned above said table, ratchet means forfeeding said grinding wheel towards said table, a solenoid adapted toactuate said ratchet means. and a switch adapted upon being closed toenergize said solenoid, and means carried by said table for periodicallyclosing said switch.

4. In a machine of the character described, a rotatable work holdingtable, a plurality of work holding chucks carried by said table, sizingand dressing means carried by said table intermediate ot a pair of saidwork holding chucks, a grinding wheel supported above said table, meansfor feeding said grinding wheel toward said table, and means carried bysaid table intermediate 0! a work holding chuck and said sizing anddressing means for actuating said grinding wheel feeding means, wherebysaid wheel will be sized and dressed intermediate or the passage 01 twoof said work holding chucks.

JULIUS V. BERGFELDT.

